Power stage and power module design to minimize parasitic inductance for multilevel inverter and converter

The subject disclosure relates to electric inverters for converting direct current to alternating current, and, in particular, to an inverter design that reduces the occurrence of parasitic inductance in the inverter.

An inverter circuit has an inherent power loop in which high current flows from a high voltage side to a low voltage side and back. This power loop generates magnetic fields, which produce a parasitic inductance for any current path that crosses through it. Accordingly, it is desirable to design an inverter to reduce the occurrence of parasitic inductance.

In one exemplary embodiment, a power module for an inverter is disclosed. The power module includes a high side bus, a low side bus and an alternating current (AC) output bus. The high side bus includes a first switch, wherein a high side current is configured to flow through the first switch in a first direction. The low side bus includes a second switch, wherein a low side current is configured to flow through the second switch in the first direction. The low side bus is parallel to the high side bus. The alternating current (AC) output bus is parallel to the high side bus and the low side bus, wherein an output current flows through the AC output bus in a second direction opposite to the first direction.

In addition to one or more of the features described herein, the high side bus and the low side bus are coplanar to each other within a first plane and the AC output bus is in a second plane.

In addition to one or more of the features described herein, the power module further includes a first heat sink coupled to the first plane and a second heat sink coupled to the second plane.

In addition to one or more of the features described herein, the high side bus is in a first plane, the low side bus in in a second plane parallel to the first plane, and the AC output bus is in a third plane, and one of the third plane is between the first plane and the second plane, the second plane is between the first plane and the third plane, and the first plane is between the second plane and the third plane.

In addition to one or more of the features described herein, a first magnetic field is generated by the high side current, a second magnetic field is generated by the low side current, and a third magnetic field is generated by the AC output current, wherein the first magnetic field, the second magnetic field and the third magnetic field cancel each other to minimize or reduce an occurrence of a parasitic inductance in a commutation loop.

In addition to one or more of the features described herein, the first switch and the second switch are coplanar to each other in a first plane and a third switch and a fourth switch are coplanar to each other in a second plane parallel to the first plane, wherein the AC output bus is between the first plane and the second plane.

In addition to one or more of the features described herein, the power module further includes a first plane, a second plane and a third plane, each parallel to each other, wherein the AC output bus includes a first AC output bus disposed between the first plane and the second plane and a second AC output bus disposed between the second plane and the third plane.

In addition to one or more of the features described herein, the first AC output bus connects to switches in the first plane and in the second plane at an end of the power module and the second AC output bus connects to switches in the second plane and in the third plane at the end of the power module.

In addition to one or more of the features described herein, the second AC output bus connects to switches in the second plane and in the third plane at a first end of the power module and the first AC output bus connects to switches in the first plane and in the second plane at a second end of the power module.

In addition to one or more of the features described herein, the inverter is one of a T-type inverter, an H-type inverter, and an X-type inverter.

In another exemplary embodiment, a vehicle is disclosed. The vehicle includes an inverter having a power module. The power module includes a high side bus including a first switch, wherein a high side current is configured to flow through the first switch in a first direction, a low side bus including a second switch, the low side bus parallel to the high side bus, wherein a low side current is configured to flow through the second switch in the first direction, and an AC output bus parallel to the high side bus and the low side bus, wherein an output current flows through the AC output bus in a second direction opposite to the first direction.

In addition to one or more of the features described herein, the high side bus and the low side bus are coplanar to each other within a first plane and the AC output bus is in a second plane.

In addition to one or more of the features described herein, the vehicle further includes a first heat sink coupled to the first plane and a second heat sink coupled to the second plane.

In addition to one or more of the features described herein, the high side bus is in a first plane, the low side bus in in a second plane parallel to the first plane, and the AC output bus is in a third plane, and one of the third plane is between the first plane and the second plane, the second plane is between the first plane and the third plane, and the first plane is between the second plane and the third plane.

In addition to one or more of the features described herein, a first magnetic field of the high side current, a second magnetic field of the low side current, and a third magnetic field generated by the AC output current cancel each other to minimize or reduce an occurrence of a parasitic inductance in a commutation loop.

In addition to one or more of the features described herein, the first switch and the second switch are coplanar to each other in the first plane of switches and a third switch and a fourth switch are coplanar to each other in a second plane of switches parallel to the first plane of switches, wherein the AC output bus is between the first plane of switches and the second plane of switches.

In addition to one or more of the features described herein, the vehicle further includes a first plane of switches, a second plane of switches and a third plane of switches, each parallel to each other, wherein the AC output bus includes a first AC output bus disposed between the first plane of switches and the second plane of switches and a second AC output bus disposed between the second plane of switches and the third plane of switches.

In addition to one or more of the features described herein, the first AC output bus connects to switches in the first plane of switches and the second plane of switches at an end of the power module and the second AC output bus connects to switches in the second plane of switches and the third plane of switches at the end of the power module.

In addition to one or more of the features described herein, the second AC output bus connects to switches in the second plane of switches and the third plane of switches at a first end of the power module and the first AC output bus connects to switches in the first plane of switches and the second plane of switches at a second end of the power module.

In addition to one or more of the features described herein, wherein the inverter is one of a T-type inverter, an H-type inverter, and an X-type inverter.

The above features and advantages, and other features and advantages of the disclosure are readily apparent from the following detailed description when taken in connection with the accompanying drawings.

The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

In accordance with an exemplary embodiment,shows a vehicle, which includes a vehicle bodydefining, at least in part, an occupant compartment. The vehicle bodyalso supports various vehicle subsystems including a propulsion system, and other subsystems to support functions of the propulsion systemand other vehicle components, such as a braking subsystem, a suspension system, a steering subsystem, and others.

The vehiclemay be an electrically powered vehicle (EV), a hybrid vehicle or any other vehicle. In an embodiment, the vehicleis an electric vehicle that includes multiple motors and/or drive systems. Any number of drive units may be included, such as one or more drive units for applying torque to front wheels (not shown) and/or to rear wheels (not shown). The drive units are controllable to operate the vehiclein various operating modes, such as a normal mode, a high-performance mode (in which additional torque is applied), all-wheel drive (“AWD”), front-wheel drive (“FWD”), rear-wheel drive (“RWD”) and others.

For example, the propulsion systemis a multi-drive system that includes a front drive unitfor driving front wheels, and rear drive units for driving rear wheels. The front drive unitincludes a front electric motorand a front inverter(e.g., front power inverter module or FPIM), as well as other components such as a cooling system. A left rear drive unitL includes an electric motorL and an inverterL. A right rear drive unitR includes an electric motorR and an inverterR. The inverters,L andR (e.g., power inverter units or PIMs) each convert direct current (DC) power from a high voltage (HV) battery systemto poly-phase (e.g., two-phase, three-phase, six-phase, etc.) alternating current (AC) power to drive the front electric motorand rear electric motorsL andR.

As shown in, the drive systems feature separate electric motors. However, embodiments are not so limited. For example, instead of separate motors, multiple drives can be provided by a single machine that has multiple sets of windings that are physically independent.

As also shown in, the drive systems are configured such that the front electric motordrives front wheels (not shown) and the rear electric motorsL andR drive rear wheels (not shown). However, embodiments are not so limited, as there may be any number of drive systems and/or motors at various locations (e.g., a motor driving each wheel, twin motors per axle, etc.). In addition, embodiments are not limited to a dual drive system, as embodiments can be used with a vehicle having any number of motors and/or power inverters.

In the propulsion system, the front drive unit, left rear drive unitL and right rear drive unitR are electrically connected to the battery system. The battery systemmay also be electrically connected to other electrical components (also referred to as “electrical loads”), such as vehicle electronics (e.g., via an auxiliary power module or APM), heaters, cooling systems and others. The battery systemmay be configured as a rechargeable energy storage system (RESS).

In an embodiment, the battery systemincludes a plurality of separate battery assemblies, in which each battery assembly can be independently charged and can be used to independently supply power to a drive system or systems. For example, the battery systemincludes a first battery assembly such as a first battery sub-packconnected to the front inverter, and a second battery sub-pack. The first battery sub-packincludes a plurality of battery modules, and the second battery sub-packincludes a plurality of battery modules. Each battery module,includes a number of individual cells (not shown). In various embodiments, one or more of the battery packs can include a MODACS (Multiple Output Dynamically Adjustable Capacity) battery.

Each of the front electric motorand the rear electric motorsL andR is a three-phase motor having three phase motor windings. However, embodiments described herein are not so limited. For example, the motors may be any poly-phase machines supplied by poly-phase inverters, and the drive units can be realized using a single machine having independent sets of windings.

The battery systemand/or the propulsion systemincludes a switching system having various switching devices for controlling operation of the battery packsand, and selectively connecting the battery packsandto the front drive unit, left rear drive unitL and right rear drive unitR. The switching devices may also be operated to selectively connect the first battery sub-packand the second battery sub-packto a charging system. The charging system can be used to charge the first battery sub-packand the second battery sub-pack, and/or to supply power from the first battery sub-packand/or the second battery sub-packto charge another energy storage system (e.g., vehicle-to-vehicle (V2V) and/or vehicle-to-everything (V2X) charging). The charging system includes one or more charging modules. For example, a first onboard charging module (OBCM)is electrically connected to a charge portfor charging to and from an AC system or device, such as a utility AC power supply. A second OBCMmay be included for DC charging (e.g., DC fast charging or DCFC).

In an embodiment, the switching system includes a first switching devicethat selectively connects the first battery sub-packto the inverters,L andR, and a second switching devicethat selectively connects the second battery sub-packto the inverters,L andR. The switching system also includes a third switching device(also referred to as a “battery switching device”) for selectively connecting the first battery sub-packto the second battery sub-packin series.

Any of various controllers can be used to control functions of the battery system, the switching system and the drive units. A controller includes any suitable processing device or unit and may use an existing controller such as a drive system controller, an RESS controller, and/or controllers in the drive system. For example, a controllermay be included for controlling switching and drive control operations as discussed herein.

The controllermay include processing circuitry that may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality. The controllermay include a non-transitory computer-readable medium that stores instructions which, when processed by one or more processors of the controller, implement a method of heating a battery pack, according to one or more embodiments detailed herein.

shows an electrical systemof the vehiclein an embodiment. The electrical systemincludes a batteryor DC power source, an inverterfor converting the DC power to and from AC power, and a motorthat operates using the AC power. The motoris generally a 3-phase motor. The inverterincludes at least three branches,,of switches. Each switch includes switches which control conversion of the DC power to AC power along the branch. In an embodiment, the switches include a transistor having a diode that spans from the source to the drain of the transistor. The transistor can be controlled by a gate voltage to control the flow of current through the transistor. The transistor can be an insulated-gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET) or any other suitable transistor.

shows a schematic diagramof a branch(such as branch, for example) of the inverterof. The branchincludes a high sideand a low side. The high sideincludes a high voltage buscoupled to a positive DC voltage and a first switch(SW) between the high voltage bus and a node A. The low sideincludes a low voltage buscoupled to a negative DC voltage and a second switch(SW) between the low voltage bus and the node A. An AC output busprovides output current from node A.

shows a power modulethat corresponds to the branchof the schematic diagramof. The power moduleextends from a first endto a second end. The power moduleincludes a high side buscorresponding to the high voltage busand which includes a first switch devicecorresponding to the first switch(SW). The power moduleincludes a low side buscorresponding to the low voltage busand which includes a second switch devicecorresponding to the second switch(SW). The first switch deviceand the second switch deviceare each in the form of a plane or a flat die. An AC output buscorresponds to the AC output busand is located between the first switch deviceand the second switch device. The AC output busis in the form of a flat plate.

The first switch device, the second switch deviceand the AC output busare aligned between the first endand the second end. The first switch deviceand the second switch deviceconnect to their respective voltage sources at the first end. At the second end, the first switch device, the second switch deviceand the AC output busconnect to each other at connector. High side currentflows through the first switch devicein a first direction (e.g., from the first endto the second end), thereby producing a high-side magnetic field BHS (first magnetic field). Low side currentflows through the second switch devicein the first direction, thereby producing a low-side magnetic field BLs (second magnetic field). The AC output currentflows through the AC output busin a second direction opposite the first direction and thereby creates an AC output magnetic field BAC (third magnetic field). As a result of the arrangement of the power module, the high-side magnetic field BHS and the low-side magnetic field Bus cancel the AC output magnetic field BAC at the location of the AC output bus. This cancellation minimizes or reduces the occurrence of parasitic inductance in a commutation loop that includes the high side current (e.g., current through high side busand first switch device), the low side current (e.g., current through low side busand second switch device) and the AC output current (e.g., current through connectorand AC output bus), thereby reduces ringing effects and electromagnetic interference.

show possible stacking arrangements for the power modulein various embodiments.shows a first stacking arrangement. The high-side (HS)(which includes the high voltage busand the first switch) lie within a first plane. The low-side (LS)(which includes the low voltage busand the second switch) lie within a second planethat is separate from and parallel to the first plane. The AC output buslies within a third plane. The third planeis parallel to, and is disposed between, the first planethe second plane.

shows a second stacking arrangement. The first plane(high-side), second plane(low-side) and third plane(AC output bus) are parallel to each other. The second planeis disposed between the first planeand the third plane.

shows a third stacking arrangement. The first plane(high-side), second plane(low-side) and third plane(AC output bus) are parallel to each other. The first planeis disposed between the second planeand the third plane.

shows another stack arrangementfor the power module. The high side(including the high voltage busand the first switch) lie within a first planar die. The low side(including the low voltage busand the second switch) lie within a second planar diethat is coplanar within the first planar die. The AC output busis disposed within a third planar dielocated to one side (i.e., above or below) of the first planar dieand second planar die. The width Wof the third planar diecan be selected to be approximately equal to the sum of the width Wof the first planar dieand the width WLs of the second planar die.

shows a schematic diagramof a T-type branch of an inverter. The T-type branch includes a positive voltage busthat includes a first switch SW, a negative voltage busthat includes a second switch SW, and a neutral busthat includes a third switch SWand a fourth switch SW. The neutral busis connected to neutral voltage. The positive voltage bus, negative voltage bus, the neutral busand an AC output pathconnect to each other at a node A.

shows a bus stackthat corresponds to the T-type branch shown in the schematic diagram. The bus stackincludes a high side bus, a low side bus, and a neutral bus. The high side buscorresponds to the positive voltage bus. The low side buscorresponds to the negative voltage bus. The neutral buscorresponds to the neutral bus. A first AC output busand a second AC output buscorrespond to the AC output path.

The bus stackextends from a first endto a second end. At the first end, high side busconnects to DC+ voltage, the low side busconnects to DC-voltage, and the neutral busconnects to a neutral voltage. At the second end, connectorconnects the second ends of the high side bus, the low side bus, the neutral bus, the first AC output busand the second AC output bus.

The high side bus, the low side busand the neutral buseach form planar dies which are arranged parallel to each other. The first AC output busis disposed between the high side busand the neutral bus. The second AC output busis disposed between the neutral busand the low side bus. High side current(flowing through the high side bus), low side current(flowing through the low side bus) and neutral current(flowing through the neutral bus) flow from the first endto the second end. The AC output current flows through one or more of the first AC output busand the second AC output busin a second direction (e.g., from the second endto the first end) that is opposite the first direction.

The high side magnetic field produced by the high side currentflowing through the high side bus, the low side magnetic field produced by the low side currentflowing through the low side bus, and the neutral bus magnetic field produced by the neutral currentflowing through the neutral buscancel each other at the first AC output bus. Also, the high side magnetic field produced by the high side currentflowing through the high side bus, the low side magnetic field produced by the low side currentflowing through the low side busand the neutral bus magnetic field produced by the neutral currentflowing through the neutral buscancel each other at the second AC output bus.

shows a bus stackfor the T-type branch of the inverter, in another embodiment. The high side bus(and switch SW) and the low side bus(and switch SW) reside next to each other in the same plane. The neutral bus(and third switch SWand fourth SW) is located to one side of the high side busand the low side bus. An AC output busis disposed between the neutral bus(on one side) and the high side busand low side bus(on an opposite side). These buses are connected to each other at the connectorlocated at a second endof the bus stack.